Switchboard incandescent lamp.



No. 728,060. A PATENTED MAY 12, 1903. .A. D. WHIPPLE. SWITGHBOARDINGANDESGENT LAMP.

APPLICATION FILED JAN. 27, 190 8.

N0 MODEL.

NlTED STATES ALLEN D. WHIPPLE, OF CHICAGO,

rammed May 12, 1905.

"PATENT FFrcE.

ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD AND SUPPLY COMPANY, OFCHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIS.

SPECIFICATION forming part of Letters Patent No. 728.060, dated May 12,1903.

Application filed January 27, 1902. Serial lilo. 91,355. (No model.)

- useful Improvement in Switchboard Incandescent Lamps, (Case No. 52,)of which the following is a specification.

My invention relates to the new and useful improvements in switchboardincandescent lamps such as are used for signaling purposes in and abouttelephone-switchboards, although it will be apparent that they may beused in any desired relation."

The object of the invention is to provide a lamp of the characterdescribed whichis more efficient and more durable than those'heretoforeknown, which is more convenient to manipulate, cheaper to manufacture,and which is of improved appearance.

My invention is illustrated by the aid of the accompanying -drawings, inwhichthe same reference-numerals designate like parts throughout theseveral views, and in which Figure 1 is a perspective view of a lampembodying my improvements. Fig. 2 is a similar view of the lamp-bulb.Fig. 3 is a like view of one of the lamp-terminals. Fig. 4'is aperspective view of the other terminal. Fig. I 5 is a similar viewof thelamp cap or base'.= Fig. 6 is a side view, partly in section, of thecomplete lamp. Fig. 7 is a view'of the lamp in a jack as it is' used inpractice. :Fig. 8 illustrates the manner of using the tool "employed forinserting the lamps into and witli- I drawing them from the jacks. Fig.9 isa section of the cap opposite of that shown in Fig. 6; and Fig. 10represents the cross-section of the terminal on the line 10 10, Fig. 4.

In the figures, 2 designates the glass bulb of'the lamp, which ispreferably of the form shown and in which the end of the bulb is roundor spherical to improve the illuminatin gs.

sides of the bulb 2, as illustrated in the draw- The features ofconstruction thus far described may be carried out in any other mannerdesired, although I prefer the arrangement shown and described.

The metallic contact-strips 5 5, forming the terminals of the lamp, arepreferably of the form shownthat is, they extend along the sides ofthe'bulb for some distance and are curved or arc-shaped in cross-sectionto cause them to closely fit the bulb. At their inner ends they arecurved inwardly, as shown at 6, to conform to the shape of the end ofthe bulb 2. The ends 7 of the terminals are made narrower than the mainportion thereof and are preferably arc-shaped in cross-section, as shownin enlarged scale in Fig. 10, to strengthen them. They preferably extendbeyond the bulb, as shown. Their extreme ends 8 are bent outward. tobetter hold the cement used to securethe cap in place, although, ofcourse, other equivalent designs could be employed to accomplish "thesame purpose. These terminals, which are conveniently out and stampedfrom sheet-brass, are designed to be securely cemented to the glass bulbin the position shown in Figs. 1 and .6,'a terminal 4. of the filamentbeing soldered to each. The curved or hollowed portion of the terminalsinto whichthe end of the bulb fits increases the cementing-so rface ofthe two and provides in addition a mechanical supporting connectionbetween them. The body portions of these terminals are adapted to beengaged by the contact-terminals of the lampsockets, the latter beingusually in the form of lamp-jacks, as seen in Fig. 7, in whichcontact-springs 9 9 are suitably supported and are adapted to engage theterminals 5 when the lamps are inserted therein. These springs 9 9- areconnected in the'circuit in which it is desired to include the lamp.They are of flat spring metal, and accordingly the terminals 5 arepreferably provided with longitudinal raised ribs 10, equidistant'fromthe center line and of a suflicient height to cause them to bear equallywith the central portion of the terminals upon the jack spring 9. Theseribs thus serve the double function of providing additional electricalcontact-surface and preventing the lamps from'be-ing turned out of theproper position either during their insertion or thereafter.

In other lamps of this general type trouble is experienced in theleakage of current between the terminals caused by the absorption ofmoisture by the wood placed between them. Again, the wood is liable tochar, and thus reduce the efficiency of the device, besides being liableto cause destructive fires. Trouble is also caused in prior devices bythe terminals of the lamps catching upon the jack-springs when it isattempted to insert the lamps in the jacks, the terminals being thustorn off the bulbs. Myinvention seeks to avoid these difficulties byproviding a cap 11, preferably of the form shown in the drawings,adapted to slip over the extended ends of the terminals and to becemented in place thereon by a suitable cement 12. This cap is ofnon-combustible material to prevent charring and burning andnon-absorbent in character to prevent absorbing moisture. Lava is foundto be suitable for the purpose and is preferred; but so far as somefeatures of this portion of my invention are concerned other materialmay be substituted. Afurther advantage of lava resides in the fact thatacids or soldering salts and similar compounds do not afiect it. Thecement used may be of any suitable kind to electrically insulate theterminals and at the same time mechanically connect the parts together.It will be obvious that in the form shown the cement adheres to bothterminals and bulb, whereby all assist in holding the cap 11 in place,and the cement secures all together. The ends 8 of the terminals and theend of the lamp may obviously be constructed of the form desired toincrease or decrease this holding action. So, too, the terminals or bulbalone may be entirely depended upon to sustain the cap by suitablyforming'them, so far as certain features and claims are concerned. Thebody of the cap is cylindrical in form, and its closed end iswedge-shaped, the beveled or wedge faces 13 being placed in line withthe terminals 5, whereby the springs 9 9 of the jacks are spread apartand guided upon the terminals 5 5 as the lamps are inserted in thejacks. The fiat sides of the Wedge prevent the lamp from being insertedin the jack in any but the proper position. The cylindrical portion ofthe cap is of such a size that its sides are in substantial alinementwith the outer faces of the terminals,whereby the jacksprings moreeasily slide upon and off the lamp. (Jurving the terminals inwardlypermits the use of a cap of this small character and at the same timeprovides ample room for the cement to fill in about the ends of theterminals. The cap thus entirely covering and inclosing the ends of theterminals prevents them from catching upon the jacksprings and beingtorn oi the bulb.

These lamps are placed in jacks, as stated, and are located beneath thesurface of the board upon which the jacks are placed, a

covering of translucent glass 14. of the desired color being inserted inthe jack-opening to protect the lamp and provide a more efiicientsignal.

It is the practice to insert and withdraw lamps of this character bymeans of an implement of the kind shown in Fig. 8, having two springtongues or jaws, such as 15, which are adapted to he slipped over thelamp-bulb, the tongues 15 passing over the bulb between the edges of theterminals 5 5. As new constructed the terminals of the lamps have squareupper ends, and the tongue 15 catches such ends and tends to tear theterminals from the bulbs. To prevent this in my lamp, the terminals haverounded ends and corners 16, whereby when the tool is slipped over thebulb, even though the lamp is in the jack and the position of theterminals cannot be seen, the tongues are guided into the spaces betweenthe terminals, and their connection with the bulb is not severed.

From the foregoing it will be apparent that I have provided a lamp whichis at once simple, complete, and efilcient, which is not subject to theusual objections and disadvantages,which embodies in addition many noveland advantageous features, and which is capable of being manufactured atcomparatively small cost.

The invention has been described with reference to the particularconstruction shown; but it will be evident that the same is capable ofmany mechanical variations and modifications, and I therefore do notwish it to be limited in all its phases and aspects to those so shownand described.

What I claim as my invention, and wish to secure by Letters Patent, is

1. In a lamp of the kind described, the combination with a bulb, ofcontact-strips secured thereto and forming the terminals of the lamp, aninsulating-cap fitting over said terminals, and cement within the cap tosecure it in place, substantially as described.

2. In a lamp of the kind described, the combination with a cylindricallamp-bulb, of contact-strips secured to the said bulb and forming theterminals for the lamp, said strips being bent inwardly to follow thecurve of the end of the bulb, an insulating-cap having its outer surfacesubstantially flush with the straight portions of said strips, andcement within the cap and surrounding the bent ends of said strips,substantially as described.

3. In a lamp of the kind described, the combination with a cylindricalbulb, of contactstrips secured thereto and forming the terminals of thelamp, said strips extending beyond the end of the bulb and havingtransversely-projecting portions, a cap inclosing said portions, andcement within said cap and surrounding the ends of the terminals andportions, substantially as described.

4. In a lamp of the kind described, the combination with a cylindricalbulb, of contact- ICC strips secured thereto and forming the terminalsof the lamp, said strips extending beyond the end of the bulb and havingtheir ends bent at an angle, a cap surrounding said ends, and cementfilling said cap and filling in around said ends, substantially asdescribed.

5. In a lamp of the kind described, the combination with a cylindricalbulb, of contactstrips secured thereto, a cap fittingover the ends ofsaid strips, and cement filling said cap and engaging the end of thebulb to thereby secure all parts together, substantially as described. v

6. In a lamp of the kind described, the combination with a bulb, ofcontact-strips secured thereto and forming the terminals of the lamp,and a hollow insulating-cap fitting over the ends of said terminals andsecured thereon, substantially as described.

7. In a lamp of the kind described, the combination with a bulb, ofcontact-strips secured thereto forming the terminals of the lamp, and anon-combustible hollow insulating-cap for the lamp slipped over the endsof the terminals and secured thereon, substantially as described.

8. In a lamp of the kind described, the combination with a bulb, ofcontact-strips secured thereto forming the terminals of the lamp, and ahollow non-absorbent and noncombustible insulatingcap for the lampplaced over the ends of said terminals and secured in place thereon,substantially as described.

9. In a lamp of the kind described, the combination with a bulb, ofcontact-strips cemented thereto and forming the terminals of the lamp, anon-absorbent and non-combustible insulating-cap for the lamp, and acoment filling for the cap to secure it in place, substantially asdescribed.

10. In a lamp of the kinddescribed,the combination with a bulb, ofcontact-strips secured to said bulb and forming the-terminals of thelamp, said strips being curved inwardly at the end of the bulb, and abase for the lamp comprising a cap having its outer surfacesubstantially flush with thecontact portions of said strips, fittingover the ends of said terminals and filled with a suitable cement tosecure the same in place, substantially as described.

11. In a lamp of the kind described,the combination with a cylindricallamp-bulb having a bulging lower end, of contact-strips extendinglongitudinally thereof and projecting beyond the end of the same, saidstrips being transversely curved throughout their length to fit the bulband'curvedinwardly at the ends to form a pocket in which the end ofthebulb'fits, and a suitable base for the lamp secured to saidprojecting ends ofthe terminals, substantially as described.

tirely inclosing the ends of said strips, and means to secure the samein place thereon, substantially as described.

13. In alamp ofthe kind described,the com bination with'a cylindricalbulb, of contactstrips secured thereto, and a hollow cap of insulationfitted to the endof the bulb and over the ends of the terminals, afillingfor said cap to secure the same in place, said cap having awedge-shaped end, the wedging-faces thereof being in alinement with thesaid strips, substantially as described. 7

14. Inalampofthekinddescribed,thecombination with a cylindrical bulb, ofcontactstrips secured to and along the sides of the bulb and formingthelamp-terminals, said strips having rounded upper ends to'permit thereadyinsertion of the lamp into the jaws or tongues of the removingimplement,whereby the said terminals are prevented frombeling torn off,substantially as described. 15. In a lamp of the kind described,thecombination with a cylindrical bulb, of a pair of contact-stripsconnected to the sides thereof and forming the terminalsof the lamps,said terminals extending .beyond'the end of the bulb, and a suitablebase for the lamp secured.

to said extended ends of the terminals, said terminals having theirupper ends rounded to permit the ready application of the removingimplement without tearing the same off, substantially as described.

16. In a lamp of the kind described,the com bination with a cylindricalbulb having a smooth cylindrical surface, of a pair of contact-stripscemented to the sides thereof and forming the terminals of'the lamps,said terminals extending beyond the end of the bulb, and a suitable basefor the-lamp secured to said extended ends of the terminals, saidterminals having their upper ends rounded to transversely curved tolaterallystrengthen the same, and an insulating-base for the lamp,-substantially as described.

18. In a lamp of the kind described,the combination with a cylindricalbulb, contacts secured along the sides thereof and forming the terminalsof thelamp, anda lava cap fitting overthe ends of said contacts andsecured thereon,substantially as described.

19. The combination with a cylindrical glass bulb, of thin sheet-metalterminals cemented to the sides of the bulb, said-terminals being curvedtransversely to conform to the'scurvature ofthebulb and following thecurve of thebulbat its lower end,'said terminals "also having narrowlower ends extending beyond.

the end-of the bulb-and also transversely &

curved and having their extreme ends bent outwardly, a hollowinsulating-cap of substantially the same diameter as the bulb placedover said extended ends of the terminals, and an insulating-cementinside of said cap and filling in around the extended ends of saidterminals to secure said cap in place and all parts together and toprovide a solid insulating-base for the lamp, substantially asdescribed.

20. Thecombination withacylindricalglass bulb, of thin sheet-metalterminals extending longitudinally of and cemented to the sides of saidbulb, a filament for the lamp having its connections soldered to saidterminals, longitudinal ridges upon each sideof and equidistant from thecenter line of said terminals,

\ said terminals being curved transversely so terminals having alsonarrowed ends extending beyond the ends of the bulb, said extended endsbeing also transversely curved to increase their strength and havingtheir extreme ends bent outwardly, a hollow cap of lava havingsubstantially the same diameter as the bulb, said cap being placed overthe said extended ends of the terminals and fitting at its upper edgeagainst the said terminals and an insulating-cement filling for saidcap, said cement filling the space within said cap and around theextended ends of said terminals and the lower end of the bulb andserving to bind said parts together, substantially as described.

In witness whereof I hereunto subscribe my name in the presence of twowitnesses.

ALLEN D. WHIPPLE. Witnesses:

F. W. DUNBAR, ROBERT LEWIS AMES.

